1. Field of the Invention
The present inventions relates to pressure balancing of internal combustion engines in general, and more particularly to a method and an apparatus for automatic pressure balancing of an internal combustion engine.
2. Description of the Prior Art
Industrial, stationary large-bore, slow-speed gaseous fuel operated internal combustion engines with cam-actuated gaseous fuel direct injector valves, such as Cooper-Bessemer 10V-250, are typically used in the natural gas pipeline industry, and in other fringe applications, and are well known in the art. The above stationary, gaseous fueled, large-bore, slow-speed engines often produce excessive exhaust emissions when the work load on the engine including multiple power cylinders is not shared equally among individual the power cylinders. Combustion pressure imbalance leads to some of the cylinders being overloaded and other cylinders having very poor and/or incomplete combustion. The overloaded cylinders will produce excessive levels of NOx, while the under-loaded cylinders with their late/poor combustion tend to produce excessive amounts of formaldehydes and CO. Also, the overloaded cylinders may have a tendency to experience detonation leading to wear and tear on mechanical parts and bearings, while the cylinders with poor combustion cause excessive fuel consumption (thus, the inordinate fuel expenses) because unburned fuel is being dumped to the exhaust system. Currently, these engines are equipped with manually operated balancing valves to adjust fuel delivery to each cylinder in order to pressure balance the power cylinder loading. The adjustment is typically done manually by an engine operator on an infrequent basis such as weekly or monthly. At many sites balancing is done at a much greater time interval. Unfortunately, as operating conditions of the engine change due to changes to an engine load and an engine speed, fuel quality variations, an inlet air temperature, humidity, ignition and mechanical problems, etc., the engine's balance is affected, thus the engine balance is not maintained during periods between the manual balance adjustments.
Therefore, the stationary, large-bore, slow-speed gaseous fuel operated internal combustion engines are susceptible to improvements that may enhance their performance and reduce operating cost. With this in mind, a need exists to develop a method and apparatus for automatic, continuous pressure balancing of an internal combustion engine with improved performance, inexpensive, and providing low operating cost.